Windows Vista/7: The next time you have a bunch of files to rename, don't hit enter after renaming the first file. Instead, hit tab to quickly highlight the next filename. Hitting F2 will also rename multiple files automatically based on the first filename.

The tab shortcut is a lot faster than clicking on each file and waiting the second or so until it can be renamed. (Use Shift+Tab to go to the file right above).

With the F2 shortcut, you can select multiple files and give them all the same name with sequential numbering (1), (2), etc. This might be useful for naming photos in a series, for example.